Christmas trees are assemblies of valves and other components used at well sites to control the flow of oil or gas out of the well and the flow of other fluids, such as frac fluid into the well. A traditional Christmas tree is shown in FIG. 1. The Christmas tree 10 may include two gate valves 12, 14, a central connector 16, and a swab valve 18 having a common axial bore (not shown). An upper end of the swab valve 18 may terminate at a cap 20. A lower end of the lower gate valve 12 may terminate at a wellhead connector 22. Four wing valves 24a-24d may be connected to the central connector in a transverse direction. A frac inlet (26 in FIG. 2) may also be connected to the central connector 16.
The Christmas tree 10 may have, for example, a height of approximately fourteen to fifteen feet, a width of approximately twelve to thirteen feet and a weight of approximately twenty-eight thousand pounds. An operator may have to use a lift or a platform to operate the wing valves 24a-24d and/or the swab valve 18. This may make assembly and use of the Christmas tree 10 more consuming of time, personnel, and/or equipment, and may add more safety concerns to the assembly and operation. The Christmas tree 10 may be too large to transport fully assembled, so the Christmas tree 10 may have to be assembled at a well site. The wing valves 24a-24d, the swab valve 18, and the gate valves 12, 14 may be capped at a single end, which may make the Christmas tree 10 difficult to clean because the opposite end of the valves may not be opened, thereby providing a “trap” for debris in the valve.
FIG. 2 illustrates a traditional well site including a Christmas tree 10. A frac inlet 26 is connected the central connector 16 of the Christmas tree 10. A frac line 28 is connected to the frac inlet 28. A flow line 30 and a pump line 32 are connected to the wing valves 24a, 24d. The frac line 28, the flow line 30, and the pump line 32 may have to be lifted a significant height off of the ground to be connected to the Christmas tree 10. This may make assembly of the system more difficult and failure of the Christmas tree 10 and/or the frac line 28, the flow line 30, and the pump line 32 more likely.